Preparation method of water-based acrylic polyurethane coating with water resistance and solvent resistance

Abstract

The invention relates to a preparation method of a water-based acrylic polyurethane coating with water resistance and solvent resistance, and belongs to the technical field of polymer coatings. A functional additive with a sulfonate group, a tetrafluorobenzene ring, an amide group, a quaternary ammonium salt group and a hydroxyl group is prepared, lipophilic groups (the sulfonate group, the tetrafluorobenzene ring and the amide group) are located in the middle of a molecular chain, piperazine groups are located at the two ends of the molecular chain, and the quaternary ammonium salt group and the hydroxyl group are connected with nitrogen atoms of the piperazine groups at the two ends. The piperazine group has a certain steric hindrance, so that the winding of quaternary ammonium salt groups and hydroxyl groups at two sides can be avoided, and the extensibility and the distribution range of the quaternary ammonium salt groups and the hydroxyl groups are improved. The additive not only can endow the emulsion with good stability, but also can be used as an active component to be cross-linked and cured together with the acrylate emulsion and the polyurethane curing agent to form a coating, and the comprehensive performance of the coating is improved.

Description

Technical Field

[0001] The present invention relates to a preparation method of a waterborne acrylic polyurethane coating with water resistance and solvent resistance, and belongs to the technical field of polymer coatings. Background Art

[0002] Polyurethane resin, namely polyurethane resin, contains a certain number of urethane bonds formed by the reaction of isocyanate and polyol. Waterborne polyurethane coating refers to a coating formed by dissolving or dispersing polyurethane resin in water with water as the solvent. Waterborne polyurethane coating uses water as the basic medium and has the advantages of non-flammability, low odor, no environmental pollution, energy saving, and convenient construction. According to the packaging form, waterborne polyurethane coatings can be divided into one-component coatings and two-component coatings. One-component coatings can be directly used alone, but their comprehensive performance is poor. Two-component coatings are composed of a waterborne hydroxyl-containing active component and a polyurethane curing agent. When the two are used in combination, a crosslinking curing reaction can occur to improve the comprehensive performance of the coating.

[0003] The film-forming process of waterborne two-component polyurethane coatings includes the following processes: ① volatilization of volatile substances (solvents, water), ② co-condensation of polyol and polyisocyanate particles, ③ reaction of polyisocyanate and water, ④ reaction of polyol and polyisocyanate. Therefore, the addition amount of the isocyanate curing agent in waterborne two-component polyurethane coatings is often excessive. Most of the waterborne polyols in waterborne two-component polyurethane coatings are emulsion-type acrylate polyols, which are prepared by emulsion polymerization of acrylate monomers containing hydroxyl groups, such as hydroxyethyl methacrylate or hydroxypropyl methacrylate, with other acrylate monomers. A certain amount of emulsifier is required during the preparation of emulsion-type acrylate polyols, and these small molecule emulsifiers will reduce the water resistance and solvent resistance of the coating after the film is formed.

[0004] With the improvement of the comprehensive performance requirements for waterborne coatings, it is urgent to develop a waterborne acrylic polyurethane coating with good water resistance and solvent resistance. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of a waterborne acrylic polyurethane coating with water resistance and solvent resistance, so as to solve the problem that the emulsifier added during the preparation of waterborne acrylic polyurethane coatings will reduce the water resistance and solvent resistance of the coating.

[0006] The present invention provides a method for preparing a waterborne acrylic polyurethane coating with water resistance and solvent resistance, comprising the following steps: mixing a functional additive, a monomer mixture, an initiator and water for a reaction to obtain a waterborne acrylate emulsion, and then mixing the waterborne acrylate emulsion and an isocyanate curing agent to obtain a waterborne acrylic polyurethane coating with water resistance and solvent resistance; the monomer mixture consists of methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate, and the mass ratio of methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate is 27-30:7-10:5-8:3-4:6-8; the mass ratio of the functional additive to the monomer mixture is 7-11:100; the structure of the functional additive is as follows:

[0007]

[0008] Wherein, R is a C4-C12 alkyl group; R1 is a fluoromethyl group or a trifluoromethyl group.

[0009] Preferably, the R is a C6-C8 alkyl group.

[0010] Preferably, the R1 is a trifluoromethyl group.

[0011] Preferably, the initiator is potassium persulfate, and the mass ratio of potassium persulfate to the monomer mixture is 0.2-0.5:100.

[0012] Preferably, the method for the mixing reaction is as follows: mixing the functional additive and water to obtain a mixed solution, and dropping a potassium persulfate solution and 8-12% of the total amount of the monomer mixture into the mixed solution under stirring and at a polymerization temperature, stirring and reacting for 30-50 min, then continuously dropping the remaining monomer mixture, after the dropping is completed, continuously stirring and reacting for 3-5 h, and after the reaction is completed, adjusting the pH to 7-7.5 to obtain a waterborne acrylate emulsion.

[0013] Preferably, the preparation method of the functional additive is as follows: 4-(chlorosulfonyl) benzoyl chloride is successively reacted with 2,3,5,6-tetrafluoroterephthalenediamine and 2-(N,N-di-tert-butylpiperazinyl) ethanol to obtain an organic fluorosulfonate grafted tert-butylpiperazine; then the organic fluorosulfonate grafted tert-butylpiperazine is reacted with an organic solution of hydrogen chloride to obtain an organic fluorosulfonate grafted piperazine; then the organic fluorosulfonate grafted piperazine is reacted with an epoxide to obtain an organic fluorosulfonate grafted piperazine polyfluorohydric alcohol; finally, the organic fluorosulfonate grafted piperazine polyfluorohydric alcohol and a halogenated hydrocarbon are subjected to a quaternization reaction to obtain the functional additive; the molar ratio of 4-(chlorosulfonyl) benzoyl chloride, 2,3,5,6-tetrafluoroterephthalenediamine and 2-(N,N-di-tert-butylpiperazinyl) ethanol is 2:1:2; the epoxide is 2-trifluoromethylethylene oxide or epifluoropropane; the halogenated hydrocarbon is one of 1-chlorobutane, 1-chlorohexane, 1-chlorooctane and 1-chlorododecane.

[0014] Preferably, the method for successively reacting 4-(chlorosulfonyl) benzoyl chloride with 2,3,5,6-tetrafluoroterephthalenediamine and 2-(N,N-di-tert-butylpiperazinyl) ethanol is as follows: first, 4-(chlorosulfonyl) benzoyl chloride and 2,3,5,6-tetrafluoroterephthalenediamine are mixed and reacted at 8-15°C for 5-8 h, and then the mixed reaction system and 2-(N,N-di-tert-butylpiperazinyl) ethanol are mixed and reacted at 25-35°C for 4-6 h.

[0015] Preferably, the method for reacting the organic fluorosulfonate grafted tert-butylpiperazine with an organic solution of hydrogen chloride is as follows: a dioxane solution of the organic fluorosulfonate grafted tert-butylpiperazine with a mass fraction of 30-40% and a dioxane solution of hydrogen chloride with a concentration of 1.8-2.2 mol / L are mixed and reacted for 5-8 h, then sodium hydroxide is added to adjust the pH of the reacted system to 8-8.5, and then impurity removal and purification are carried out to obtain the organic fluorosulfonate grafted piperazine; the mass ratio of the dioxane solution of hydrogen chloride to the solution of the organic fluorosulfonate grafted tert-butylpiperazine is 3:1.8-2.

[0016] Preferably, the reaction temperature of the organic fluorosulfonate grafted piperazine and the epoxide is 90-95°C, and the reaction time is 5-7 h; the molar ratio of the organic fluorosulfonate grafted piperazine and the epoxide is 1:4.2-4.5.

[0017] Preferably, the reaction temperature of the organic fluorosulfonate grafted piperazine polyfluorohydric alcohol and the halogenated hydrocarbon for quaternization reaction is 80-90°C, and the reaction time is 5-8 h; the molar ratio of the organic fluorosulfonate grafted piperazine polyfluorohydric alcohol and the halogenated hydrocarbon is 1:5-6.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) By preparing a functional additive with sulfonate groups, tetrafluorobenzene rings, amide groups, quaternary ammonium salt groups, and hydroxyl groups, the lipophilic groups (sulfonate groups, tetrafluorobenzene rings, amide groups) are located in the middle of the molecular chain, the piperazine groups are located at both ends of the molecular chain, and the quaternary ammonium salt groups and hydroxyl groups are connected to the nitrogen atoms of the piperazine groups at both ends, forming a branched structure. The piperazine groups have a certain steric hindrance, which can prevent the quaternary ammonium salt groups and hydroxyl groups on both sides from winding, and improve the stretching property and distribution range of the quaternary ammonium salt groups and hydroxyl groups. Using the additive as an emulsifier to prepare a waterborne acrylate emulsion, each group cooperates with each other and works together, making the additive have both hydrophilicity and lipophilicity, exerting an emulsifying effect, and making the waterborne acrylate emulsion have good dilution stability, storage stability, and calcium ion stability; in addition, the tetrafluorobenzene rings, sulfonate esters, and amide groups in the middle part of the additive molecular chain have good water resistance, acid-base resistance, and solvent resistance. The hydroxyl groups evenly distributed at both ends of the molecular chain form a stable branched structure. After cross-linking with a curing agent, a network structure with a higher degree of cross-linking is formed, further improving the water resistance, solvent resistance, abrasion resistance, and weather resistance of the coating.

[0020] (2) The functional additive prepared in the present invention can, while endowing the emulsion with good stability, serve as an active component to cross-link and cure with the acrylate emulsion and the polyurethane curing agent together to form a coating and improve the comprehensive performance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1H NMR spectrum of the functional additive prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following examples are intended to further illustrate the content of the present invention rather than limit the protection scope of the present invention.

[0023] Specific examples of the preparation method of the waterborne acrylate polyurethane coating with water resistance and solvent resistance of the present invention are as follows:

[0024] Example 1

[0025] The preparation method of the waterborne acrylate polyurethane coating with water resistance and solvent resistance in this example includes the following steps:

[0026] (1) Add 4-(chlorosulfonyl)benzoyl chloride and chloroform into a reaction kettle, stir until 4-(chlorosulfonyl)benzoyl chloride is fully dissolved, and obtain a 4-(chlorosulfonyl)benzoyl chloride solution with a mass fraction of 12%.

[0027] Add 2,3,5,6-tetrafluoroterephthalamine and chloroform into a reaction kettle, stir until 2,3,5,6-tetrafluoroterephthalamine is fully dissolved to obtain a 2,3,5,6-tetrafluoroterephthalamine solution with a mass fraction of 35%. Then adjust and control the temperature of the 2,3,5,6-tetrafluoroterephthalamine solution to -5°C, start stirring, and dropwise add a 4-(chlorosulfonyl)benzoyl chloride solution into the 2,3,5,6-tetrafluoroterephthalamine solution. After the dropping is completed, add triethylamine, and then raise the temperature to 8°C and stir for reaction for 5 h. Among them, the molar ratio of 2,3,5,6-tetrafluoroterephthalamine, 4-(chlorosulfonyl)benzoyl chloride and triethylamine is 1:2:2.1.

[0028] (2) Add 2-(N,N-ditert-butoxycarbonylpiperazin)ethanol and chloroform into a reaction kettle, stir until 2-(N,N-ditert-butoxycarbonylpiperazin)ethanol is fully dissolved to obtain a 2-(N,N-ditert-butoxycarbonylpiperazin)ethanol solution with a mass fraction of 30%. The structure of 2-(N,N-ditert-butoxycarbonylpiperazin)ethanol is as follows:

[0029]

[0030] Dropwise add the 2-(N,N-ditert-butoxycarbonylpiperazin)ethanol solution into the reaction kettle after the stirring reaction in step (1). After the dropping is completed, add triethylamine, then raise the temperature to 25°C, stir for reaction for 4 h, filter, rotary evaporate the filtrate to remove the solvent to obtain a concentrated solution, and subject the concentrated solution to column chromatography purification to obtain an organic fluorosulfonate grafted tert-butyl piperazine. Among them, the molar ratio of 2-(N,N-ditert-butoxycarbonylpiperazin)ethanol, 4-(chlorosulfonyl)benzoyl chloride and triethylamine is 1:1:1.1, and the eluent used for column chromatography purification is composed of petroleum ether, ethyl acetate and dichloromethane with a volume ratio of 5:1:1. The structure of the organic fluorosulfonate grafted tert-butyl piperazine is as follows:

[0031]

[0032] (3) Add the organic fluorosulfonate grafted tert-butyl piperazine and dioxane into a reaction kettle, stir until the organic fluorosulfonate grafted tert-butyl piperazine is fully dissolved to obtain an organic fluorosulfonate grafted tert-butyl piperazine solution with a mass fraction of 30%.

[0033] Add a dioxane solution of hydrogen chloride with a concentration of 1.8 mol / L to a stirring reaction kettle. Adjust the temperature of the dioxane solution of hydrogen chloride in the stirring reaction kettle to -2 °C. Start stirring, and dropwise add an organic fluorosulfonate grafted tert-butyl ester piperazine solution into the dioxane solution of hydrogen chloride. After the addition is completed, adjust the temperature of the materials in the stirring reaction kettle to room temperature, and continue stirring and reacting for 5 h. Then add sodium hydroxide to adjust the pH of the materials in the stirring reaction kettle to 8. Then add an appropriate amount of water and dichloromethane to the stirring reaction kettle for extraction. Rotate and evaporate and dry the obtained organic phase to obtain an organic fluorosulfonate grafted piperazine; wherein, the mass ratio of the dioxane solution of hydrogen chloride to the organic fluorosulfonate grafted tert-butyl ester piperazine solution is 3:1.8, and the structure of the organic fluorosulfonate grafted piperazine is as follows:

[0034]

[0035] (4) Introduce nitrogen into the reaction kettle, and then add the organic fluorosulfonate grafted piperazine, 2-trifluoromethyl epoxyethane, and ethyl acetate into the reaction kettle. Heat to 90 °C, stir and react for 5 h, then rotate and evaporate to remove ethyl acetate to obtain a concentrate. Purify the concentrate by column chromatography to obtain an organic fluorosulfonate grafted piperazine polyfluorinated alcohol; wherein, the molar ratio of the organic fluorosulfonate grafted piperazine to 2-trifluoromethyl epoxyethane is 1:4.2, the mass ratio of the organic fluorosulfonate grafted piperazine to ethyl acetate is 1:0.8, the eluent used for column chromatography purification consists of methanol, ethyl acetate, and dichloromethane with a volume ratio of 1.2:9:15, and the structure of the organic fluorosulfonate grafted piperazine polyfluorinated alcohol is as follows:

[0036]

[0037] (5) Add the organic fluorosulfonate grafted piperazine polyfluorinated alcohol, halogenated hydrocarbon, and acetonitrile to a stirring reaction kettle. Heat to 80 °C, stir and reflux for 5 h, then rotate and evaporate the reaction system to remove acetonitrile to obtain a concentrate. Purify the concentrate by column chromatography to obtain a functional additive; wherein, the molar ratio of the organic fluorosulfonate grafted piperazine polyfluorinated alcohol to the halogenated hydrocarbon is 1:5, the mass ratio of the organic fluorosulfonate grafted piperazine polyfluorinated alcohol to acetonitrile is 1:1.2, the halogenated hydrocarbon is 1-chlorobutane, the eluent used for column chromatography purification consists of methanol and chloroform with a volume ratio of 1.8:30, and the 1H NMR spectrum of the functional additive is as Figure 1 shown, and the structure of the functional additive is as follows:

[0038]

[0039] (6) Add methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate into a stirring reaction kettle, stir evenly to obtain a monomer mixture; wherein, the mass ratio of methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate is 27:7:5:3:6;

[0040] Add the functional additive prepared in step (5) and water into the reaction kettle according to a mass ratio of 1:10, stir evenly to obtain a mixed solution, control the temperature of the materials in the reaction kettle at 65 °C, and then dropwise add a potassium persulfate solution with a mass fraction of 4% and 8% of the total amount of the monomer mixture into the reaction kettle under stirring conditions. After the addition of the potassium persulfate solution and the monomer mixture is completed, continue stirring and reacting for 30 min, then dropwise add the remaining monomer mixture into the reaction kettle, continue stirring and reacting for 3 h, cool down to 45 °C, add ammonia water into the reaction kettle, and adjust the pH of the materials in the reaction kettle to 7 to obtain an aqueous acrylate emulsion; wherein, the mass ratio of the functional additive to the monomer mixture is 7:100, and the mass ratio of potassium persulfate to the monomer mixture is 0.2:100.

[0041] (7) Stir the aqueous acrylate emulsion prepared in step (6) and an aqueous isocyanate curing agent (Covestro Bayhydur XP2487) evenly to obtain an aqueous acrylic polyurethane coating with water resistance and solvent resistance; the molar ratio of the isocyanate group in the aqueous isocyanate curing agent to the hydroxyl group in the aqueous acrylate emulsion is 1.2:1.

[0042] Example 2

[0043] The preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in this example includes the following steps:

[0044] (1) Add 4-(chlorosulfonyl)benzoyl chloride and chloroform into a reaction kettle, stir until 4-(chlorosulfonyl)benzoyl chloride is fully dissolved to obtain a 4-(chlorosulfonyl)benzoyl chloride solution with a mass fraction of 20%;

[0045] Add 2,3,5,6-tetrafluoroterephthalamine and chloroform into a reaction kettle, stir until 2,3,5,6-tetrafluoroterephthalamine is fully dissolved to obtain a 2,3,5,6-tetrafluoroterephthalamine solution with a mass fraction of 40%, then control the temperature of the 2,3,5,6-tetrafluoroterephthalamine solution at 0 °C, start stirring, and dropwise add the 4-(chlorosulfonyl)benzoyl chloride solution into the 2,3,5,6-tetrafluoroterephthalamine solution. After the addition is completed, add triethylamine, and then raise the temperature to 10 °C and stir and react for 7 h; wherein, the molar ratio of 2,3,5,6-tetrafluoroterephthalamine, 4-(chlorosulfonyl)benzoyl chloride and triethylamine is 1:2:2.2.

[0046] (2) Add 2-(N,N-ditert-butylpiperazinyl)ethanol and chloroform to the reaction kettle, stir until 2-(N,N-ditert-butylpiperazinyl)ethanol is completely dissolved to obtain a 2-(N,N-ditert-butylpiperazinyl)ethanol solution with a mass fraction of 35%. The structure of 2-(N,N-ditert-butylpiperazinyl)ethanol is as follows:

[0047]

[0048] Dropwise add the 2-(N,N-ditert-butylpiperazinyl)ethanol solution to the reaction kettle after the stirring reaction in step (1). After the dropwise addition, add triethylamine, then raise the temperature to 30 °C, stir and react for 5 h, filter, rotary evaporate the filtrate to remove the solvent to obtain a concentrated solution, and purify the concentrated solution by column chromatography to obtain organofluorobenzenesulfonate grafted tert-butylpiperazine. Among them, the molar ratio of 2-(N,N-ditert-butylpiperazinyl)ethanol, 4-(chlorosulfonyl)benzoyl chloride and triethylamine is 1:1:1.2. The eluent used for column chromatography purification is composed of petroleum ether, ethyl acetate and dichloromethane with a volume ratio of 5:1:1. The structure of organofluorobenzenesulfonate grafted tert-butylpiperazine is as follows:

[0049]

[0050] (3) Add organofluorobenzenesulfonate grafted tert-butylpiperazine and dioxane to the reaction kettle, stir until organofluorobenzenesulfonate grafted tert-butylpiperazine is completely dissolved to obtain an organofluorobenzenesulfonate grafted tert-butylpiperazine solution with a mass fraction of 35%.

[0051] Add a dioxane solution of hydrogen chloride with a concentration of 2 mol / L to the stirring reaction kettle, adjust the temperature of the dioxane solution of hydrogen chloride in the stirring reaction kettle to 0 °C, start stirring, dropwise add the organofluorobenzenesulfonate grafted tert-butylpiperazine solution to the dioxane solution of hydrogen chloride. After the dropwise addition, adjust the temperature of the materials in the stirring reaction kettle to room temperature, continue stirring and reacting for 6 h, then add sodium hydroxide to adjust the pH of the materials in the stirring reaction kettle to 8, and then add appropriate amounts of water and dichloromethane to the stirring reaction kettle for extraction. Rotary evaporate and dry the obtained organic phase to obtain organofluorobenzenesulfonate grafted piperazine. Among them, the mass ratio of the dioxane solution of hydrogen chloride to the organofluorobenzenesulfonate grafted tert-butylpiperazine solution is 3:1.8. The structure of organofluorobenzenesulfonate grafted piperazine is as follows:

[0052]

[0053] (4) Nitrogen is introduced into the reaction kettle, and then the organic fluorosulfonate grafted piperazine, 2-trifluoromethyl oxirane and ethyl acetate are added to the reaction kettle. It is heated to 92 °C and stirred for reaction for 6 h. Then, rotary evaporation is carried out to remove ethyl acetate to obtain a concentrate. The concentrate is purified by column chromatography to obtain the organic fluorosulfonate grafted piperazine polyfluorohydric alcohol; wherein, the molar ratio of the organic fluorosulfonate grafted piperazine to 2-trifluoromethyl oxirane is 1:4.3, the mass ratio of the organic fluorosulfonate grafted piperazine to ethyl acetate is 1:1, the eluent used for column chromatography purification is composed of methanol, ethyl acetate and dichloromethane with a volume ratio of 1.2:9:15, and the structure of the organic fluorosulfonate grafted piperazine polyfluorohydric alcohol is as follows:

[0054]

[0055] (5) The organic fluorosulfonate grafted piperazine polyfluorohydric alcohol, halogenated hydrocarbon and acetonitrile are added to the stirring reaction kettle. It is heated to 85 °C and stirred and refluxed for reaction for 6 h. Then, the reaction system is rotary evaporated to remove acetonitrile to obtain a concentrate. The concentrate is purified by column chromatography to obtain the functional additive; wherein, the molar ratio of the organic fluorosulfonate grafted piperazine polyfluorohydric alcohol to the halogenated hydrocarbon is 1:6, the mass ratio of the organic fluorosulfonate grafted piperazine polyfluorohydric alcohol to acetonitrile is 1:1.3, the halogenated hydrocarbon is 1-chlorobutane, the eluent used for column chromatography purification is composed of methanol and chloroform with a volume ratio of 1.8:30, and the structure of the functional additive is as follows:

[0056]

[0057] (6) Methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate are added to the stirring reaction kettle and stirred evenly to obtain a monomer mixture; wherein, the mass ratio of methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate is 28:9:6:5:7;

[0058] The functional additive prepared in step (5) and water are added to the reaction kettle according to a mass ratio of 1:10 and stirred evenly to obtain a mixed solution. The temperature of the materials in the reaction kettle is controlled at 70 °C. Then, a 5% potassium persulfate solution and 10% of the total amount of the monomer mixture are added dropwise to the reaction kettle under stirring conditions. After the addition of the potassium persulfate solution and the monomer mixture is completed, stirring reaction is continued for 40 min. Then, the remaining monomer mixture is added dropwise to the reaction kettle and stirring reaction is continued for 4 h. The temperature is lowered to 45 °C, and ammonia water is added to the reaction kettle to adjust the pH of the materials in the reaction kettle to 7 to obtain an aqueous acrylate emulsion; wherein, the mass ratio of the functional additive to the monomer mixture is 9:100, and the mass ratio of potassium persulfate to the monomer mixture is 0.3:100.

[0059] (7) Stir the aqueous acrylate emulsion and the aqueous isocyanate curing agent (Covestro Bayhydur XP2487) prepared in step (6) evenly to obtain an aqueous acrylic polyurethane coating with water resistance and solvent resistance; the molar ratio of the isocyanate group in the aqueous isocyanate curing agent to the hydroxyl group in the aqueous acrylate emulsion is 1.2:1.

[0060] Example 3

[0061] The preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in this example includes the following steps:

[0062] (1) Add 4-(chlorosulfonyl)benzoyl chloride and chloroform into the reaction kettle, stir until 4-(chlorosulfonyl)benzoyl chloride is fully dissolved to obtain a 4-(chlorosulfonyl)benzoyl chloride solution with a mass fraction of 25%.

[0063] Add 2,3,5,6-tetrafluoroterephthalamide and chloroform into the reaction kettle, stir until 2,3,5,6-tetrafluoroterephthalamide is fully dissolved to obtain a 2,3,5,6-tetrafluoroterephthalamide solution with a mass fraction of 45%. Then adjust and control the temperature of the 2,3,5,6-tetrafluoroterephthalamide solution to 2°C, start stirring, and dropwise add the 4-(chlorosulfonyl)benzoyl chloride solution into the 2,3,5,6-tetrafluoroterephthalamide solution. After the dropping is completed, add triethylamine, and then raise the temperature to 15°C and stir and react for 8 h; among them, the molar ratio of 2,3,5,6-tetrafluoroterephthalamide, 4-(chlorosulfonyl)benzoyl chloride and triethylamine is 1:2:2.3.

[0064] (2) Add 2-(N,N-di-tert-butylpiperazinyl)ethanol and chloroform into the reaction kettle, stir until 2-(N,N-di-tert-butylpiperazinyl)ethanol is fully dissolved to obtain a 2-(N,N-di-tert-butylpiperazinyl)ethanol solution with a mass fraction of 40%; the structure of 2-(N,N-di-tert-butylpiperazinyl)ethanol is as follows:

[0065]

[0066] Dropwise add the 2-(N,N-di-tert-butylpiperazinyl)ethanol solution into the reaction kettle after the stirring reaction in step (1). After the dropping is completed, add triethylamine, then raise the temperature to 35°C, stir and react for 6 h, filter, rotary evaporate the filtrate to remove the solvent to obtain a concentrated solution, and purify the concentrated solution by column chromatography to obtain an organic fluorosulfonate grafted tert-butyl piperazine; among them, the molar ratio of 2-(N,N-di-tert-butylpiperazinyl)ethanol, 4-(chlorosulfonyl)benzoyl chloride and triethylamine is 1:1:1.3, and the eluent used for column chromatography purification consists of petroleum ether, ethyl acetate and dichloromethane with a volume ratio of 5:1:1; the structure of the organic fluorosulfonate grafted tert-butyl piperazine is as follows:

[0067]

[0068] (3) Add the organic fluorosulfonate grafted tert-butyl piperazine and dioxane into the reaction kettle, stir until the organic fluorosulfonate grafted tert-butyl piperazine is completely dissolved, and obtain an organic fluorosulfonate grafted tert-butyl piperazine solution with a mass fraction of 40%.

[0069] Add the dioxane solution of hydrogen chloride with a concentration of 2.2 mol / L into the stirring reaction kettle, adjust the temperature of the dioxane solution of hydrogen chloride in the stirring reaction kettle to 3 °C, start stirring, and dropwise add the organic fluorosulfonate grafted tert-butyl piperazine solution into the dioxane solution of hydrogen chloride. After the dropping is completed, adjust the temperature of the materials in the stirring reaction kettle to room temperature, continue stirring and reacting for 8 h, then add sodium hydroxide to adjust the pH of the materials in the stirring reaction kettle to 8, then add appropriate amounts of water and dichloromethane into the stirring reaction kettle for extraction, and rotary evaporate and dry the obtained organic phase to obtain the organic fluorosulfonate grafted piperazine; wherein, the mass ratio of the dioxane solution of hydrogen chloride to the organic fluorosulfonate grafted tert-butyl piperazine solution is 3:1.8, and the structure of the organic fluorosulfonate grafted piperazine is as follows:

[0070]

[0071] (4) Pass nitrogen into the reaction kettle, then add the organic fluorosulfonate grafted piperazine, 2-trifluoromethyl epoxyethane and ethyl acetate into the reaction kettle, heat to 95 °C, stir and react for 7 h, then rotary evaporate to remove ethyl acetate to obtain a concentrate, and purify the concentrate by column chromatography to obtain the organic fluorosulfonate grafted piperazine polyfluorinated alcohol; wherein, the molar ratio of the organic fluorosulfonate grafted piperazine to 2-trifluoromethyl epoxyethane is 1:4.5, the mass ratio of the organic fluorosulfonate grafted piperazine to ethyl acetate is 1:1.1, the eluent used for column chromatography purification is composed of methanol, ethyl acetate and dichloromethane with a volume ratio of 1.2:9:15, and the structure of the organic fluorosulfonate grafted piperazine polyfluorinated alcohol is as follows:

[0072]

[0073] (5) Add the organic fluorosulfonate grafted piperazine polyfluorinated alcohol, halogenated hydrocarbon and acetonitrile into the stirring reaction kettle, heat to 90 °C, stir and reflux for 8 h, then rotary evaporate the reacted system to remove acetonitrile to obtain a concentrate, and purify the concentrate by column chromatography to obtain the functional additive; wherein, the molar ratio of the organic fluorosulfonate grafted piperazine polyfluorinated alcohol to the halogenated hydrocarbon is 1:6, the mass ratio of the organic fluorosulfonate grafted piperazine polyfluorinated alcohol to acetonitrile is 1:1.3, the halogenated hydrocarbon is 1-chlorobutane, the eluent used for column chromatography purification is composed of methanol and chloroform with a volume ratio of 1.8:30, and the structure of the functional additive is as follows:

[0074]

[0075] (6) Methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate are added to a stirring reaction kettle and stirred evenly to obtain a monomer mixture; wherein, the mass ratio of methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate is 30:10:8:4:8;

[0076] The functional additive prepared in step (5) and water are added to the reaction kettle according to a mass ratio of 1:10 and stirred evenly to obtain a mixed solution. The temperature of the material in the reaction kettle is controlled at 75 °C, and then a 5% potassium persulfate solution and 12% of the total monomer mixture are added dropwise to the reaction kettle under stirring conditions. After the addition of the potassium persulfate solution and the monomer mixture is completed, stirring reaction is continued for 50 min, and then the remaining monomer mixture is added dropwise to the reaction kettle and stirring reaction is continued for 5 h. The temperature is lowered to 45 °C, and ammonia water is added to the reaction kettle to adjust the pH of the material in the reaction kettle to 7.5 to obtain an aqueous acrylate emulsion; wherein, the mass ratio of the functional additive to the monomer mixture is 11:100, and the mass ratio of potassium persulfate to the monomer mixture is 0.5:100.

[0077] (7) The aqueous acrylate emulsion prepared in step (6) and an aqueous isocyanate curing agent (Covestro Bayhydur XP2487) are stirred evenly to obtain an aqueous acrylic polyurethane coating with water resistance and solvent resistance; the molar ratio of isocyanate groups in the aqueous isocyanate curing agent to hydroxyl groups in the aqueous acrylate emulsion is 1.3:1.

[0078] Example 4

[0079] The preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in this example is only different from the preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in Example 1 in that 2-trifluoromethyl epoxyethane in step (4) is replaced by epoxyfluoropropane in the preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in this example.

[0080] Example 5

[0081] The preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in this example is only different from the preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in Example 1 in that the halogenated hydrocarbon in step (5) of the preparation method of the aqueous acrylic polyurethane coating with water resistance and solvent resistance in this example is 1-chlorohexane.

[0082] Example 6

[0083] The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this example is only different from that of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in Example 1 in that the halogenated hydrocarbon in step (5) of the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this example is 1-chlorooctane.

[0084] Example 7

[0085] The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this example is only different from that of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in Example 1 in that the halogenated hydrocarbon in step (5) of the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this example is 1-chlorododecane.

[0086] Comparative Example 1

[0087] The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is only different from that of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in Example 1 in that the preparation method of the functional additive in the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is as follows:

[0088] (1) Add 2,3,5,6-tetrafluoroterephthaloyl chloride and chloroform into the reaction kettle, stir until 2,3,5,6-tetrafluoroterephthaloyl chloride is fully dissolved, and obtain a 2,3,5,6-tetrafluoroterephthaloyl chloride solution with a mass fraction of 12%;

[0089] Add 2-(N,N-di-tert-butylpiperazinyl)ethanol and chloroform into the reaction kettle, stir until 2-(N,N-di-tert-butylpiperazinyl)ethanol is fully dissolved, and obtain a 2-(N,N-di-tert-butylpiperazinyl)ethanol solution with a mass fraction of 30%; then adjust and control the temperature of the 2-(N,N-di-tert-butylpiperazinyl)ethanol solution at -5°C, start stirring, drop the 2,3,5,6-tetrafluoroterephthaloyl chloride solution into the 2-(N,N-di-tert-butylpiperazinyl)ethanol solution. After the dropping is completed, add triethylamine, then raise the temperature to 8°C, stir and react for 5 h, filter, rotary evaporate the filtrate to remove the solvent, obtain a concentrated solution, and purify the concentrated solution by column chromatography to obtain organofluorine-grafted tert-butylpiperazine; wherein, the molar ratio of 2-(N,N-di-tert-butylpiperazinyl)ethanol, 2,3,5,6-tetrafluoroterephthaloyl chloride and triethylamine is 2:1:2.1.

[0090] (2) Add organofluorine-grafted tert-butylpiperazine and dioxane into the reaction kettle, stir until organofluorine-grafted tert-butylpiperazine is fully dissolved, and obtain an organofluorine-grafted tert-butylpiperazine solution with a mass fraction of 30%;

[0091] Add a dioxane solution of hydrogen chloride with a concentration of 1.8 mol / L to a stirring reaction kettle. Adjust the temperature of the dioxane solution of hydrogen chloride in the stirring reaction kettle to -2 °C. Start stirring, and dropwise add an organic fluorine grafted tert-butyl ester piperazine solution to the dioxane solution of hydrogen chloride. After the addition is completed, adjust the temperature of the material in the stirring reaction kettle to room temperature, and continue stirring and reacting for 5 h. Then add sodium hydroxide to adjust the pH of the material in the stirring reaction kettle to 8. Then add an appropriate amount of water and dichloromethane to the stirring reaction kettle for extraction. Rotate and evaporate the obtained organic phase and dry it to obtain organic fluorine grafted piperazine; wherein, the mass ratio of the dioxane solution of hydrogen chloride to the organic fluorine grafted tert-butyl ester piperazine solution is 3:1.8.

[0092] (3) Introduce nitrogen into the reaction kettle, and then add organic fluorine grafted piperazine, 2-trifluoromethyl epoxyethane and ethyl acetate to the reaction kettle. Heat to 90 °C and stir and react for 5 h. Then rotate and evaporate to remove ethyl acetate to obtain a concentrate. Purify the concentrate by column chromatography to obtain organic fluorine grafted piperazine polyfluorohydric alcohol; wherein, the molar ratio of organic fluorine grafted piperazine to 2-trifluoromethyl epoxyethane is 1:4.2, the mass ratio of organic fluorine grafted piperazine to ethyl acetate is 1:0.8, and the eluent used for column chromatography purification is composed of methanol, ethyl acetate and dichloromethane with a volume ratio of 1.2:9:15.

[0093] (4) Add organic fluorine grafted piperazine polyfluorohydric alcohol, halogenated hydrocarbon and acetonitrile to a stirring reaction kettle. Heat to 80 °C and stir and reflux for 5 h. Then rotate and evaporate the reaction system to remove acetonitrile to obtain a concentrate. Purify the concentrate by column chromatography to obtain a functional additive; wherein, the molar ratio of organic fluorine grafted piperazine polyfluorohydric alcohol to halogenated hydrocarbon is 1:5, the mass ratio of organic fluorine grafted piperazine polyfluorohydric alcohol to acetonitrile is 1:1.2, the halogenated hydrocarbon is 1-chlorobutane, the eluent used for column chromatography purification is composed of methanol and chloroform with a volume ratio of 1.8:30, and the structure of the functional additive is as follows:

[0094]

[0095] Comparative Example 2

[0096] The difference between the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example and the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in Example 1 is only that the preparation method of the functional additive in the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is as follows:

[0097] (1) Add 1,4-benzenedisulfonyl chloride and chloroform to the reaction kettle, and stir until 1,4-benzenedisulfonyl chloride is completely dissolved to obtain a 1,4-benzenedisulfonyl chloride solution with a mass fraction of 12%.

[0098] Add 2-(N,N-di-tert-butoxycarbonylpiperazin-1-yl)ethanol and chloroform into a reaction kettle, stir until 2-(N,N-di-tert-butoxycarbonylpiperazin-1-yl)ethanol is completely dissolved to obtain a 2-(N,N-di-tert-butoxycarbonylpiperazin-1-yl)ethanol solution with a mass fraction of 30%; then adjust and control the temperature of the 2-(N,N-di-tert-butoxycarbonylpiperazin-1-yl)ethanol solution to -5°C, start stirring, and dropwise add a 1,4-benzenedisulfonyl chloride solution into the 2-(N,N-di-tert-butoxycarbonylpiperazin-1-yl)ethanol solution. After the dropping is completed, add triethylamine, then raise the temperature to 25°C, stir and react for 5 h, filter, rotary evaporate the filtrate to remove the solvent to obtain a concentrated solution, and subject the concentrated solution to column chromatography purification to obtain a sulfonate-grafted tert-butyl piperazine; wherein, the molar ratio of 2-(N,N-di-tert-butoxycarbonylpiperazin-1-yl)ethanol, 1,4-benzenedisulfonyl chloride and triethylamine is 2:1:2.1.

[0099] (2) Add the sulfonate-grafted tert-butyl piperazine and dioxane into a reaction kettle, stir until the sulfonate-grafted tert-butyl piperazine is completely dissolved to obtain a sulfonate-grafted tert-butyl piperazine solution with a mass fraction of 30%.

[0100] Add a 1.8 mol / L hydrogen chloride dioxane solution into a stirring reaction kettle, adjust the temperature of the hydrogen chloride dioxane solution in the stirring reaction kettle to -2°C, start stirring, and dropwise add the sulfonate-grafted tert-butyl piperazine solution into the hydrogen chloride dioxane solution. After the dropping is completed, adjust the temperature of the materials in the stirring reaction kettle to room temperature, continue to stir and react for 5 h, then add sodium hydroxide to adjust the pH of the materials in the stirring reaction kettle to 8, and then add appropriate amounts of water and dichloromethane into the stirring reaction kettle for extraction. Rotary evaporate and dry the obtained organic phase to obtain a sulfonate-grafted piperazine; wherein, the mass ratio of the hydrogen chloride dioxane solution to the sulfonate-grafted tert-butyl piperazine solution is 3:1.8.

[0101] (3) Introduce nitrogen into the reaction kettle, then add the sulfonate-grafted piperazine, 2-trifluoromethyloxirane and ethyl acetate into the reaction kettle, heat to 90°C, stir and react for 5 h, then rotary evaporate to remove ethyl acetate to obtain a concentrate, and subject the concentrate to column chromatography purification to obtain a sulfonate-grafted piperazine polyfluorinated alcohol; wherein, the molar ratio of the sulfonate-grafted piperazine to 2-trifluoromethyloxirane is 1:4.2, the mass ratio of the sulfonate-grafted piperazine to ethyl acetate is 1:0.8, and the eluent used for column chromatography purification is composed of methanol, ethyl acetate and dichloromethane with a volume ratio of 1.2:9:15.

[0102] (4) Add sulfonate-grafted piperazine polyfluorohydric alcohol, halogenated hydrocarbon, and acetonitrile into a stirring reaction kettle, heat to 80 °C, stir and reflux for 5 h, then rotary evaporate the reacted system to remove acetonitrile to obtain a concentrate, and purify the concentrate by column chromatography to obtain a functional additive; wherein, the molar ratio of sulfonate-grafted piperazine polyfluorohydric alcohol to halogenated hydrocarbon is 1:5, the mass ratio of sulfonate-grafted piperazine polyfluorohydric alcohol to acetonitrile is 1:1.2, the halogenated hydrocarbon is 1-chlorobutane, the eluent used for column chromatography purification is composed of methanol and chloroform with a volume ratio of 1.8:30, and the structure of the functional additive is as follows:

[0103]

[0104] Comparative Example 3

[0105] The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is only different from the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in Example 1 in that the preparation method of the functional additive in step (6) of the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is as follows:

[0106] First, add benzenesulfonyl chloride and chloroform into a reaction kettle, stir until benzenesulfonyl chloride is fully dissolved to obtain a 12% by mass benzenesulfonyl chloride solution; then add 1H,1H,9H,9H-perfluoro-1,9-nonanediol and chloroform into the reaction kettle, stir until 1H,1H,9H,9H-perfluoro-1,9-nonanediol is fully dissolved to obtain a 30% by mass 1H,1H,9H,9H-perfluoro-1,9-nonanediol solution; then adjust and control the temperature of the 1H,1H,9H,9H-perfluoro-1,9-nonanediol solution at -5 °C, start stirring, drop the benzenesulfonyl chloride solution into the 1H,1H,9H,9H-perfluoro-1,9-nonanediol solution, after the dropping is completed, add triethylamine, then raise the temperature to 25 °C, stir and react for 5 h, filter, rotary evaporate the filtrate to remove the solvent to obtain a functional additive; wherein, the molar ratio of 1H,1H,9H,9H-perfluoro-1,9-nonanediol, benzenesulfonyl chloride, and triethylamine is 1:1:1.1.

[0107] Comparative Example 4

[0108] The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is only different from the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in Example 1 in that the functional additive in step (6) of the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is replaced with 2,3-dihydroxy-N,N-dimethyl-N-[3-[(1-oxodocosyl)amino]propyl]-1-propanaminium chloride.

[0109] Comparative Example 5

[0110] The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example is different from that of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in Example 1 only in that in step (6) of the preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance in this comparative example, the functional additive is replaced with a mixture composed of 2,3-dihydroxy-N,N-dimethyl-N-[3-[(1-oxodocosyl)amino]propyl]-1-propanaminium chloride with a mass ratio of 1:1 and the functional additive in Comparative Example 3.

[0111] Experimental Example 1

[0112] In order to investigate the stability of the waterborne acrylate emulsions prepared in each example and comparative example, the dilution stability, storage stability and calcium ion stability of the waterborne acrylate emulsions were respectively tested according to the corresponding standards; among them, the dilution stability was tested according to the method specified in Standard GB / T 20623-2006. The specific test method is as follows: The waterborne acrylate emulsion was diluted with distilled water to a mass fraction of non-volatile matter of 3% to obtain a dilution solution. Then, the dilution solution was placed in a graduated cylinder. After standing for 72 h, the volume of the upper clear liquid separated from the dilution solution and the volume of the lower sediment part were measured, and the percentage p1 of the volume of the upper clear liquid in the total volume of the dilution solution and the percentage p2 of the volume of the lower sediment part in the total volume of the dilution solution were calculated; the storage stability was tested according to the method specified in Standard GB / T 20623-2006. The specific test method is as follows: A certain volume of the waterborne acrylate emulsion was placed in a glass bottle, and it was ensured that 10% of the space was left in the bottle. The glass bottle was placed in a constant temperature drying oven at 50 °C, and the time T when stratification, skin formation, hard lumps or flocculation occurred in the waterborne acrylate emulsion in the glass bottle was observed and recorded. 储 The calcium ion stability was tested according to the method specified in Standard GB / T 20623-2006. The specific test method is as follows: A certain volume of the waterborne acrylate emulsion was placed in a beaker, and then a calcium chloride solution with a mass fraction of 0.5% was added to the beaker. The volume ratio of the waterborne acrylate emulsion to the calcium chloride solution was 30:1. After stirring evenly, it was poured into a stoppered graduated cylinder, and the time T when stratification, precipitation or flocculation occurred in the emulsion was observed. 钙

[0113] The test results of the stability of the waterborne acrylate emulsions prepared in each example and comparative example are shown in Table 1.

[0114] Table 1 Stability of the waterborne acrylate emulsions prepared in each example and comparative example

[0115] ​

[0116] As can be seen from Table 1, the aqueous acrylate emulsion prepared in the present invention has good stability, including dilution stability, storage stability and calcium ion stability; the above experimental results show that the functional additive prepared in the present invention has good emulsifying property. The sulfonate group, tetrafluorobenzene ring, amide group, quaternary ammonium salt group and hydroxyl group in the additive cooperate with each other and play a role together, making the additive have both hydrophilicity and lipophilicity and exerting an emulsifying effect. The lipophilic groups (sulfonate group, tetrafluorobenzene ring, amide group) are located in the middle of the molecular chain, the piperazine group is located at both ends of the molecular chain, the quaternary ammonium salt group and the hydroxyl group are connected to the nitrogen atoms of the piperazine groups at both ends, forming a branched structure. The piperazine group has a certain steric hindrance, which can prevent the quaternary ammonium salt group and the hydroxyl group on both sides from winding, improve the stretching property and distribution range of the quaternary ammonium salt group and the hydroxyl group, and thus improve the emulsifying effect.

[0117] As can be seen from Example 1 and Example 4, after replacing 2-trifluoromethylethylene oxide with epifluoropropane, due to the decrease in the number of fluorine elements in the molecular chain, the hydrophilicity and lipophilicity change, and thus the emulsion stability decreases slightly; as can be seen from Example 1 and Examples 5-7, the length of the alkyl chain in the quaternary ammonium salt also has a certain influence on the emulsion stability. As the number of carbon atoms in the halogenated hydrocarbon increases, the emulsion stability first becomes better and then worse, indicating that when the halogenated hydrocarbon is 1-chlorooctane or 1-chlorohexane, the prepared additive has the optimal emulsifying and stabilizing effect.

[0118] As can be seen from Example 1 and Comparative Examples 1-2, when the structure of the additive is changed and the sulfonate group or tetrafluorobenzene ring in the additive is removed, the hydrophilicity and lipophilicity of the additive change, resulting in poor emulsion stability. As can be seen from Example 1 and Comparative Examples 3-5, when the additive is replaced with other sulfonate alcohol emulsifiers, quaternary ammonium salts or a combination of both, the stability of the prepared emulsion is poor, indicating that compared with the additive of the present invention, conventional sulfonate and quaternary ammonium salt emulsifiers cannot better disperse and stabilize the acrylate emulsion.

[0119] Experimental Example 2

[0120] In order to investigate the comprehensive performance of the waterborne acrylic polyurethane coatings prepared in each embodiment and comparative example, the adhesion, water resistance, solvent resistance, corrosion resistance, wear resistance and weather resistance of the waterborne acrylic polyurethane coatings were tested respectively; wherein, the adhesion was tested according to the method specified in the standard GBT9286-1998, and the specific test method was as follows: the waterborne acrylic polyurethane coating was brushed on the test plate, and then left to cure and dry at room temperature for 7 days, and then 5 parallel cuts were made along the parallel and vertical directions of the long side of the test plate with a single-edged tool, and the coating was cut through with a 1mm interval between each cut, and then a tear test was performed with a tape, and the adhesion of the coating was rated according to the degree of damage to the coating after tearing according to the provisions of the standard GBT9286-1998; the materials of the test plate were cement, tinplate, glass and copper. Each sample was tested three times, and the average of the three test results was taken as the final result.

[0121] Water resistance and solvent resistance are tested according to the method specified in the standard GB 9274-1988 "Determination of resistance of paints and varnishes to liquid media". The specific test method is as follows: apply water-based acrylic polyurethane paint on the tinplate, let it stand and cure at room temperature for 7 days, then seal the edges and back of the tinplate, and then immerse the tinplate in water or the test solvent, seal it with a cover, and then observe and record the time when the coating surface changes color, bubbling, peeling, powdering or softening; the test solvents are saturated calcium hydroxide solution, 10% acetic acid solution by mass, ethanol, acetone, and toluene. Each sample is tested 3 times, and the average of the 3 test results is taken as the final result.

[0122] The corrosion resistance was tested according to the method specified in the standard GB10125-1997. The specific test method is as follows: the water-based acrylic polyurethane coating was applied to the steel plate with a 100μm wire rod coater, and then left to cure and dry at room temperature for 7 days. A blade was used to draw cross lines on the coating film, through the coating until the steel plate substrate was exposed, and the scratch was greater than 20mm from any edge of the steel plate, and the edges were sealed with wax, and then a neutral salt spray test was performed. The time when rust spots appeared on the steel plate surface and the time when the corrosion at the scratch line reached 2cm wide were observed and recorded. The smaller time when rust spots appeared on the steel plate surface and the time when the corrosion at the scratch line reached 2cm wide were used as the corrosion resistance test result of the coating. Each sample was tested three times, and the average of the three test results was used as the final result. The corrosion resistance test results are shown in Table 3.

[0123] The abrasion resistance was tested using an abrasion tester. During the test, a rubber grinding wheel was used, and the weight loss of the coating during the test was used to evaluate the abrasion resistance. Each sample was tested 3 times repetitively, and the average value of the 3 test results was taken as the final result. The weather resistance was tested according to the method specified in Standard GB / T 1865-1997. The specific test method is as follows: The waterborne acrylic polyurethane coating was brushed on a glass plate, then left to cure and dry at room temperature for 7 days. Then, the glass plate with the coated surface facing up was placed in an artificial aging test chamber for weather resistance testing, and the absolute value ΔC of the color difference between before coating aging and when the aging time was 3000 h was calculated. Each sample was tested 3 times repetitively, and the average value of the 3 test results was taken as the final result.

[0124] The test results of the adhesion, abrasion resistance, and weather resistance of the waterborne acrylic polyurethane coatings prepared in each example and comparative example are shown in Table 2, and the test results of the water resistance and solvent resistance are shown in Table 3.

[0125] Table 2 Test Results of the Adhesion, Abrasion Resistance, and Weather Resistance of the Waterborne Acrylic Polyurethane Coating

[0126]

[0127] Table 3 Test Results of the Water Resistance and Solvent Resistance of the Waterborne Acrylic Polyurethane Coating

[0128]

[0129]

[0130] As can be seen from Table 2 and Table 3, the waterborne acrylic polyurethane coating prepared in the present invention has good adhesion to a variety of substrates, and also has good water resistance, solvent resistance, abrasion resistance, and weather resistance. The above experimental results show that the functional additive prepared in the present invention can, while endowing the emulsion with good stability, act as an active component to crosslink and cure with the acrylate emulsion and the polyurethane curing agent together to form a coating and improve the comprehensive performance of the coating. The tetrafluorobenzene ring, sulfonate ester, and amide groups in the middle part of the functional additive molecular chain have good water resistance, acid-base resistance, and solvent resistance. The hydroxyl groups evenly distributed at both ends of the molecular chain form a stable branched structure. After crosslinking with the curing agent, a network structure with a higher degree of crosslinking is formed, further improving the water resistance, solvent resistance, abrasion resistance, and weather resistance of the coating.

[0131] As shown in Example 1 and Example 4, after 2-trifluoromethyl oxirane is replaced by epoxyfluoropropane, due to the reduction of fluorine element quantity in the molecular chain, the hydrophobicity of coating is reduced, and then when contacting with solvent, it is easily attacked by test solvent contact, causing performance degradation. As shown in Example 1 and Example 5-7, the alkyl chain length in quaternary ammonium salt has a certain influence on the comprehensive properties of coating, and along with the increase of alkyl chain length, water resistance, solvent resistance, wear resistance and weather resistance present a trend of first strengthening and then weakening on the whole, and the performance is optimal when the alkyl chain is hexane or octane.

[0132] It can be seen from Example 1 and Comparative Examples 1-2 that when the structure of the additive is changed and the sulfonate group or tetrafluorobenzene ring in the additive is removed, although the additive contains a branched hydroxyl structure, the middle part of the molecular chain lacks the sulfonate group or tetrafluorobenzene ring, resulting in poor solvent resistance of the additive. In addition, since the length of the middle part of the additive molecular chain becomes shorter, the cross-linking is too dense, resulting in poor wear resistance and weather resistance.

[0133] It can be seen from Example 1 and Comparative Examples 3-5 that when the additive is replaced with other sulfonate alcohol emulsifiers, quaternary ammonium salts or a combination of the two, due to the lack of chemically bonded fluorine atoms, sulfonates or quaternary ammonium salts in the additives, the coating has poor density and cannot resist damage from solvents, resulting in poor resistance.

Claims

1. A preparation method of a waterborne acrylic polyurethane coating with water resistance and solvent resistance, characterized in that, It includes the following steps: mixing a functional additive, a monomer mixture, an initiator and water for a reaction to obtain an aqueous acrylate emulsion, and then mixing the aqueous acrylate emulsion and an isocyanate curing agent to obtain an aqueous acrylic polyurethane coating with water resistance and solvent resistance; the monomer mixture consists of methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate, and the mass ratio of methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylic acid and hydroxypropyl acrylate is 27-30:7-10:5-8:3-4:6-8; the mass ratio of the functional additive to the monomer mixture is 7-11:100; the structure of the functional additive is as follows; Wherein, R is a C4-C12 alkyl group; R1 is a fluoromethyl group or a trifluoromethyl group.

2. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance according to claim 1, characterized in that, The R is a C6-C8 alkyl group.

3. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance as described in claim 1, characterized in that, The R1 is a trifluoromethyl group.

4. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance according to claim 1, characterized in that, The initiator is potassium persulfate, and the mass ratio of potassium persulfate to the monomer mixture is 0.2-0.5:

100.

5. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance according to claim 4, characterized in that, The method of the mixing reaction is as follows: mixing the functional additive and water to obtain a mixed solution, and dropping a potassium persulfate solution and 8-12% of the total amount of the monomer mixture into the mixed solution under stirring and polymerization temperature, stirring and reacting for 30-50 min, then continuously dropping the remaining monomer mixture, after the dropping is completed, continuously stirring and reacting for 3-5 h, after the reaction is completed, adjusting the pH to 7-7.5 to obtain an aqueous acrylate emulsion.

6. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance according to any one of claims 1-5, characterized in that, The preparation method of the functional additive is as follows: reacting 4-(chlorosulfonyl)benzoyl chloride with 2,3,5,6-tetrafluoroterephthalamine and 2-(N,N-ditert-butylpiperazinyl)ethanol in sequence to obtain an organic fluorosulfonate grafted tert-butylpiperazine; then reacting the organic fluorosulfonate grafted tert-butylpiperazine with an organic solution of hydrogen chloride to obtain an organic fluorosulfonate grafted piperazine; then reacting the organic fluorosulfonate grafted piperazine with an epoxy compound to obtain an organic fluorosulfonate grafted piperazine polyfluorinated alcohol; finally, carrying out a quaternization reaction on the organic fluorosulfonate grafted piperazine polyfluorinated alcohol and a halogenated hydrocarbon to obtain the functional additive; the molar ratio of 4-(chlorosulfonyl)benzoyl chloride, 2,3,5,6-tetrafluoroterephthalamine and 2-(N,N-ditert-butylpiperazinyl)ethanol is 2:1:2; the epoxy compound is 2-trifluoromethylethylene oxide or epoxyfluoropropane; the halogenated hydrocarbon is one of 1-chlorobutane, 1-chlorohexane, 1-chlorooctane and 1-chlorododecane.

7. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance according to claim 6, characterized in that, The method of reacting 4-(chlorosulfonyl)benzoyl chloride with 2,3,5,6-tetrafluoroterephthalamine and 2-(N,N-ditert-butylpiperazinyl)ethanol in sequence is as follows: first mixing and reacting 4-(chlorosulfonyl)benzoyl chloride and 2,3,5,6-tetrafluoroterephthalamine at 8-15 °C for 5-8 h, and then mixing and reacting the mixed reaction system with 2-(N,N-ditert-butylpiperazinyl)ethanol at 25-35 °C for 4-6 h.

8. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance as described in claim 6, characterized in that, The method for reacting the organic fluoro sulfonate grafted tert-butyl piperazine with hydrogen chloride in an organic solution is as follows: Mix a dioxane solution of the organic fluoro sulfonate grafted tert-butyl piperazine with a mass fraction of 30-40% and a dioxane solution of hydrogen chloride with a concentration of 1.8-2.2 mol / L and react for 5-8 h. Then add sodium hydroxide to adjust the pH of the reaction system to 8-8.5, and then carry out impurity removal and purification to obtain the organic fluoro sulfonate grafted piperazine; the mass ratio of the dioxane solution of hydrogen chloride to the solution of the organic fluoro sulfonate grafted tert-butyl piperazine is 3:1.8-2.

9. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance as described in claim 6, characterized in that, The reaction temperature between the organic fluoro sulfonate grafted piperazine and the epoxy compound is 90-95 °C, and the reaction time is 5-7 h; the molar ratio of the organic fluoro sulfonate grafted piperazine to the epoxy compound is 1:4.2-4.

5.

10. The preparation method of the waterborne acrylic polyurethane coating with water resistance and solvent resistance as described in claim 6, characterized in that, The quaternization reaction temperature between the organic fluoro sulfonate grafted piperazine polyfluorinated alcohol and the halogenated hydrocarbon is 80-90 °C, and the reaction time is 5-8 h; the molar ratio of the organic fluoro sulfonate grafted piperazine polyfluorinated alcohol to the halogenated hydrocarbon is 1:5-6.

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